The curved speed skate blade was first discussed in U.S. Pat. No. 5,320,368 (1994) to Ling. The patent discusses some of the advantages with longitudinal side bending of speed skating blades, including combinations of radius and bend for speed skating blades in said patent.
Speed skating blades are generally manufactured with an aluminum or steel longitudinal tubular structure, into which a steel blade is mounted on one side of the tube, and aluminum mounting “cups” or “arms” are attached to the opposite side of the tube to allow for the mounting and adjustment of a boot. There are two general types of speed skating blades, one being designated for short track skating on a 111 m skating track, and the other for long track skating on a 400 m skating track. The short track blades are designed to be mounted in a fixed position at the forefoot and heel of the boot as shown in FIG. 1. The mounts used on the short track blades may be changed for different heights to increase or decrease the distance between the boot and the blade depending on the preference of the skater. The most popular long track blades are designed to be mounted in a fixed position in the forefoot of the blade on a hinged arm that is not fixed to the heel of the boot, as shown in FIG. 2A. This is commonly referred to as a “clap skate” after the clapping sound that occurs when the hinge closes while skating. FIG. 2B illustrates the movement of the clap arm (20). This design allows for longer contact with the ice and more speed to be generated by the skater. The hinged clap arm design on the long track skate is not allowed to be used on a short track skate under regulation by the International Skating Union, the governing body for the sport.
Speed skate racing is generally performed with turns only in the counter-clockwise direction. To maximize stability and skating efficiency, skate boots and blades are typically configured to take advantage of the counter-clockwise turns. Blades are mounted on boots with an offset to the left, and some blades are positioned to the left in their support structure. The blade runner surface is also generally adjusted with a radius or “rocker” that complements the dimensions of the skating rink and the experience level of the skater. The radius applied to the blades for a beginning skater is normally a single radius, whereas expert level skaters might use a complex curve made of multiple radii varying over the length of the blade surface, also referred to as a compound radius. Typically, the chosen rocker is more curved at the heel and toe areas of the blade, and flatter toward the center of the blade. The center section of the blade tends to be more curved than the turn radius of the racing course.
In addition to applying a radius to the runner surface of the blade, the blades of expert skaters can be also bent to the left to take advantage of skating only in a counter-clockwise direction. For skaters using a compound radius, the bend applied to the blades can be varied according to the radius to increase the contact area of the blade with the surface of the ice, thereby increasing grip as well as allowing the skater to turn more sharply as they apply weight to that section of the blade. To illustrate this principle, for skaters who have a smaller radius applied to the toe and heel sections of their blades and a flatter radius in the center, when the blades are bent more in the toe and heel areas, as the skater applies more weight to the toe or heel sections of the blade, the blade will turn more quickly allowing the skater to change their trajectory more easily.
The bending of skate blades historically was done with a mallet, vise, or similar tool until the blade “looked right” or “felt right.” The bending process was usually applied to the blade's tube, rather than the blade runner because the blade runner is more delicate, and the tube tends to retain the applied curve better. The toe of the blade may be bent so the blade turns more sharply when a skater's weight moves forward. The heel of the blade may be bent so the blade turns more sharply when the skater's weight moves back. The entire blade can be bent in a smooth arc for increased ice contact and stability, or it may have variable curvature to allow the skater to increase or decrease their turning efficiency depending on the portion of blade they apply pressure to. There was little predictability in this process when performed with mallets and vices, and as a result, skaters were often hesitant to skate on blades bent in this manner.
In the mid-1990's, in Australia, Dennis Pennington built a purpose-specific tool for blade bending. The Pennington Blade Bender brought with it a more predictable method of applying the bend to a blade. It allowed the user to apply pressure to a lever arm and flex a portion of the blade between two anvil-like surfaces. The anvils were permanently mounted in a sliding track and could be adjusted for width to increase or decrease the size of the area being bent. Attached to the lever-arm, mounted above the anvils, was a round disk with a radius on the edge, which is like the round surface of the blades tube holder. When the lever was pushed down, the presser disc was pressed against the blade's tube, and a bend in that section of the blade resulted. The more pressure that was applied to the lever arm, the more bend was applied to the blade. The benefits of the Pennington bender included easier repeatability of bending operations, more consistent bending results, the device was portable, and the device was relatively inexpensive. After the Pennington bender was released, additional bender designs were brought to market by various competitors.
When the application of more precise radius and bend to the skate blade began to become more standard in the industry, technicians began to utilize a measurement apparatus to validate that the desired radius and bend had been correctly applied to the blade's runner surface. As discussed by Lang in U.S. Pat. No. 5,320,368 (1994), the typical measuring device measures either blade radius or bend over a 3½-inch (8.9 cm) span according to a dial indicator showing height in 1/1000-inch (0.0254 mm) increments.
There are several prior art filings for apparatuses for measuring squareness of the blade runner surface, including U.S. Pat. No. 5,345,688 A (1994), U.S. Pat. No. 5,547,416 A (1996), U.S. Pat. No. 6,481,113 B1 (2002), U.S. Pat. No. 7,434,324 B2 (2005) (also CA 2,763,023 C), U.S. Pat. No. 7,191,539 B2 (2005), U.S. Pat. No. 7,918,035 B1(2009). None of these apparatuses address the issue of measuring either radius or bend on the blade runner surfaces.
Public domain prior art for measurement apparatuses that are concerned with measuring the radius and bend on the blade runner surfaces include the Marchese radius gauge, the Maple Skate B.V. radius gauge, and the ING radius gauge.
The Marchese gauge has become the industry standard measuring apparatus and is used by most skate technicians. This gauge was developed by Paul Marchese and it can be used to measure both radius and bend on both Long Track and Short Track skate blades. The Marchese gauge's popularity has led to the adoption of utilizing a 4″ span with a dial indicator showing height in 1/1000-inch (0.254 mm) increments, and a tolerance of approximately +/−0.002″ (0.508 mm)
The Maple gauge utilizes the same basic design as the Marchese gauge but with less costly components resulting in a lower degree of accuracy, but at a lower price it offered broader access to a measuring tool.
The ING gauge, developed by Ronald van de Ing, utilizes a narrower span of approximately 2⅜″ (6.033 cm) and height measurement in 1 μm increments. This gauge also introduced the concept of using rare earth magnets in the gauge frame to aid the user in maintaining proper position of the gauge on the surface to be measured. This gauge's design limits the user to measuring Long Track blade radii above 16 meters since radii below that number will result in exceeding the dial indicators ability to measure height. The gauge is accurate with a tolerance of approximately +/−0.5 μm. Because this gauge uses a difference span distance, with a higher resolution dial indicator, it is more difficult to use because very minor changes to the radius will appear to the uneducated user to be very large changes. The design of the frame is such that the components are permanently attached and not replaceable when wear occurs. Because the rare earth magnets are permanently affixed to the frame, cleaning off steel debris that accumulates during use is very difficult. Such debris can affect the accuracy of the measurements if not removed. Further, because the magnets are installed in a position that is offset from the contact points on the frame, this design cannot be used for accurate measurement of a blade's bend as the blade runner will tend to deform when the magnet is applied.
All existing gauges utilize a dial indicator which measures the contact point height, an average height measurement across a distance between the contact points on the main body of the device. The closer the contact points are together, the more granular the resolution of the measurement becomes. Accordingly, there exists a need for an improved skate blade bending device.